Hasil untuk "Cement industries"

Subhransu Dhar, Eduardo Machado-Charry, Robert Schennach et al.

The settling of spherical balls in quiescent cement pastes of increasing age is studied. Metallic spheres with radii of 2, 2.5 and 3mm are dropped into the paste and allowed to settle, while their position is tracked using X-ray tomography. The instantaneous velocity of the spheres, calculated from their movement, is observed to be quasi-constant during their fall, and an average is estimated. The results show that the average velocity of the balls decreases logarithmically with paste age until ball stoppage, for all three ball sizes. In parallel, the rheological properties of the cement paste are measured using a rheometer with a vane geometry. The evolution of the paste static yield stress over time is evaluated, and proves to be a reliable predictor for ball stoppage. Finally, thixotropic models of increasing complexity are evaluated. These models consider four forms of structural growth and breakdown parameters, and their ability to capture the ball settling velocity as a function of paste age is compared. This emphasizes the importance of considering paste breakdown in relation to shearing of the paste when the ball passes through it.

J. Wesseling, S. Lechtenböhmer, Max Åhman et al.

Energy-intensive processing industries (EPIs) produce iron and steel, aluminum, chemicals, cement, glass, and paper and pulp and are responsible for a large share of global greenhouse gas emissions. To meet 2050 emission targets, an accelerated transition towards deep decarbonization is required in these industries. Insights from sociotechnical and innovation systems perspectives are needed to better understand how to steer and facilitate this transition process. The transitions literature has so far, however, not featured EPIs. This paper positions EPIs within the transitions literature by characterizing their sociotechnical and innovation systems in terms of industry structure, innovation strategies, networks, markets and governmental interventions. We subsequently explore how these characteristics may influence the transition to deep decarbonization and identify gaps in the literature from which we formulate an agenda for further transitions research on EPIs and consider policy implications. Furthering this research field would not only enrich discussions on policy for achieving deep decarbonization, but would also develop transitions theory since the distinctive EPI characteristics are likely to yield new patterns in transition dynamics.

Jing-Yu Liu, Yan Xia, Ying Fan et al.

Majeti Narasimha Vara Prasad

Mahipal Kasaniya, Michael DA Thomas, Ted Moffatt et al.

This paper presents the quantification of the pozzolanic reactivity of pozzolans examined in terms of compressive strength, bound water and electrical resistivity. The pozzolans studied included natural pozzolans, glass pozzolans and fly ash that were ground to four fineness levels or median particle sizes (d50) of approximately 3, 5, 10 and 15 µm. Quantitative X-ray diffraction was employed to determine the amorphous content of pozzolans. The UNB lime-reactivity test and a modified ASTM C311 activity with portland cement test were performed in mortars. In these two tests, bulk electrical resistivity measurements were conducted before measuring compressive strength. Additionally, pastes were prepared for bound water in accordance with the R3 test or ASTM C1897. While the pozzolanic reactivity for all materials tested generally improves with the fineness, one pozzolan could demonstrate a very different rate of pozzolanicity improvements compared to that of others. Bulk electrical resistivity provides a reliable assessment of pozzolanic reactivity and can help differentiate pozzolanic and pozzolanic-hydraulic materials when used in conjunction with compressive strength. The modified ASTM C311 test is also found to be suitable and effective in rapidly distinguishing pozzolans, especially slow reactive ones, from inert materials at 7 days. A novel amorphous-fineness index derived by combining the amorphous content and fineness of pozzolans to reasonably predict the pozzolanic reactivity and limitations of the index are discussed.

Hari Krishna Subramaniam, U. Johnson Alengaram, Wan Zurina Wan Jaafar

This study evaluates the effects of fineness-modified Class F fly ash (FA) on the performance of Type I and Type II Ordinary Portland Cement (OPC) mortars. FA was mechanically ground to achieve 90% (GFA1) and 98% (GFA2) passing through a 45-µm sieve, replacing OPC at 10%, 30%, and 50% by weight. Comprehensive testing included compressive strength, water demand, setting time, heat of hydration, acid resistance, and microstructural analysis. Results demonstrated that increasing FA fineness reduced water demand by up to 6.3% (Type I) and 5.9% (Type II) at 30% replacement, while enhancing long-term strength. Mortars with 10% GFA2 achieved 58.6 MPa at 56 days. Type II OPC blends exhibited superior acid resistance, with mass loss reductions of 43% (50% GFA2) compared to Type I, attributed to lower C₃A content and denser microstructures. Hydration heat decreased by 10.9% in Type II OPC, further reduced by 40% with 50% FA replacement. The microstructural analysis confirmed reduced ettringite formation and enhanced compactness in FA-modified mortars, correlating with improved durability. These findings highlight the viability of finely ground FA as a sustainable supplementary material, enabling highvolume FA utilization (up to 50%). The study provides critical insights for optimizing greener cement formulations, particularly in regions prioritizing Type II OPC for sulfate resistance and moderate heat applications, advancing Malaysia’s net-zero carbon goals through reduced clinker reliance.

Bhagyashri A. Lanjewar, Abhilasha N. Kumbalwar, Hindavi Gavali et al.

Anticipated urbanization and population growth, particularly in developing countries, are expected to boost demand for concrete, resulting in higher emissions and raw material consumption. In response to growing global sustainability awareness, various industries and countries have implemented diverse initiatives aimed at significantly reducing their greenhouse gas emissions. Alkali Activated Concrete (AAC), often known as zero cement concrete, is a viable substitute for conventional concrete. This study developed self-compacting alkali-activated concrete (SCAAC) using agro-industrial wastes and curing at ambient temperatures. The precursors were ground granulated blast furnace slag (GGBS) and fly ash (FA), which were activated with sodium hydroxide flakes and liquid sodium silicate. Co-fired bio-blended ash (BA), an agro-industrial waste, was used to partially replace river sand. The physical, chemical, mineral, and morphological properties of BA were thoroughly investigated. The BA was found suitable to use as a partial replacement for river sand in self-compacting alkali-activated concrete. The curing at ambient temperature was effective in producing a high-strength and durable concrete material. The thermal conductivity of the developed concrete was determined. The reduction in embodied energy for the developed material was calculated. The reduction in peak cooling load was found using computational modeling for cement based concrete and SCAAC. The developed concrete successfully met the specified compressive strength requirement for M30 grade concrete, achieving a value of 38.12 MPa. Reduction in embodied energy (7.37%) of the developed concrete was observed as compared to conventional concrete. Results show that the peak cooling load reduced by 35% compared to conventional concrete [1.9 W/(m.K)] due to the lower thermal conductivity of the developed material [1.247 W/(m.K)]. The use of agro-industrial wastes in the concrete mixture not only reduced the environmental impact but also utilized waste materials that would otherwise be disposed of in landfills. Overall, this study demonstrates the potential for sustainable and environmentally friendly construction materials using agro-industrial wastes.

Yong Cui, Xiwen Yin, Qiuge Yu

The use of coal gangue as aggregates to prepare concrete is an effective way to promote the sustainable development of building materials and coal industries. This study first explores the influence of water–binder ratios, cement dosage, and sand–aggregate ratios on the compressive strength of full coal gangue aggregates through response surface methodology. Then, the influence of water–binder ratio and superplasticizer synergy on the slump, compressive strength, compression characteristics, and water resistance of full coal gangue concrete was explored and its degradation mechanism was revealed. Finally, the influence of substitution rate on slump, compressive strength, hydration products, and microstructure under different water–binder ratios was explored by replacing natural stones with coal gangue coarse aggregates. The results showed that the order of influencing factors on the compressive strength of full coal gangue aggregate concrete is water–binder ratio > cement dosage > sand–aggregate ratio. Taking the maximum compressive strength as the optimization objective, the optimal mix ratio was obtained as follows: cement dosage of 450 kg/m3, water–binder ratio of 0.7, sand–aggregate ratio of 33%, and compressive strength of 8.6 MPa after 28 days of sealed curing, with an error of less than 5% compared to the predicted value; Full coal gangue aggregate concrete is limited by its own compressive strength and cannot improve its compressive strength by reducing the water–binder ratio. The lower the water–binder ratio, the higher are its water absorption rate, strength loss rate, and mass loss rate. This is mainly because coal gangue contains minerals such as water calcium zeolite and montmorillonite, which have water absorption and expansion properties; using coal gangue coarse aggregate to replace some natural crushed stone can effectively improve the water resistance of concrete. When the water–binder ratio is 0.4 and the coal gangue coarse aggregate substitution rate is 50%, it meets the requirement of compressive strength >20 MPa after 28 days of water immersion in concrete.

Xiaoyan Xu, Zhixuan Wang, Yue Him Wong et al.

Abstract Marine biofouling caused by barnacle gregarious settlement poses significant challenges to various industries and ecosystems, such as increased drag on ship hulls, elevated fuel consumption, and heightened maintenance costs. While natural chemical cues are instrumental in driving barnacle settlement, the underlying mechanisms remain incompletely understood. In this work, we investigated the effects of adenosine (Ado), a settlement pheromone of Amphibalanus amphitrite cyprids, on cyprid exploration behavior, nano-mechanical properties of footprints, and gene expression using atomic force microscopy (AFM) and omics analysis. Results indicate that Ado significantly increases the settlement rate and exploration frequency of cyprids, and enhances the expression of the settlement-inducing protein complex (SIPC, which attracts other cyprids to settle in a gregarious manner). AFM results reveal that Ado-treated cyprids exhibit enhanced adhesion, self-healing, elasticity, and mechanical strength in their footprints, which may help them resist the shear forces from seawater. Transcriptome analysis suggests that Ado triggers the up-regulation of the transcription factors FTZ-F1 and Hr39, which may activate the 20E hormonal signaling pathway and promote the settlement process. Furthermore, Ado up-regulates the cement protein genes of CP19K-like4 and CP100K, which are involved in the initial adhesion process. These findings provide valuable insights into the role of pheromones in promoting barnacle settlement and offer a deeper understanding of the mechanisms driving this behavior.

Pingping Shan

Against the background of the current global energy shortage and increasing pressure on carbon emissions, energy saving and emission reduction have become the key to the transformation and upgrading of various industries. As a key area of high energy consumption and high emissions, it is particularly important for the cement industry to improve its energy efficiency and green transformation. Based on this background, this study selects a 5000t/d new dry-process cement production line as the research object, aiming to explore the energy efficiency optimization path of cement clinker calcination system through in-depth energy-saving diagnosis. During the research process, we integrated the mechanism analysis and HDMR algorithm to construct an accurate energy consumption model of the cement clinker calcining system. The model not only shows good approximation ability to accurately reflect the energy consumption characteristics of the system, but also has excellent generalization ability, which provides the possibility of predicting the energy consumption under different working conditions. Further, we combined this model with an advanced cement production control process system for targeted energy-saving modification and optimization of the cement calcination process. The results show that this integrated approach significantly improves the energy efficiency of the cement calcination system. Specifically, the standard coal consumption per unit of product was reduced by 6.46 kgce compared with the pre-optimization period to 93.28 kgce, with an annual energy saving of up to 9,819.2 tons of standard coal (tce), while the annual carbon emission was reduced by about 6,578.9 tons of carbon dioxide (CO2).

Jan Lorenz Svensen, Wilson Ricardo Leal da Silva, Zhanhao Zhang et al.

This study presents a dynamic simulation model for the pyro-process of clinker production in cement plants. The study aims to construct a simulation model capable of replicating the real-world dynamics of the pyro-process to facilitate research into the improvements of operation, i.e., the development of alternative strategies for reducing CO2 emissions and ensuring clinker quality, production, and lowering fuel consumption. The presented model is an index-1 differential-algebraic equation (DAE) model based on first engineering principles and modular approaches. Using a systematic approach, the model is described on a detailed level that integrates geometric aspects, thermo-physical properties, transport phenomena, stoichiometry and kinetics, mass and energy balances, and algebraic volume and energy conservations. By manually calibrating the model to a steady-state reference, we provide dynamic simulation results that match the expected reference performance and the expected dynamic behavior from the industrial practices.

Nicola Cantisani, Jan Lorenz Svensen, Shanmugam Perumal et al.

We present a novel dynamic model of an electric flash clay calcination plant. Calcined kaolinite-rich clay has been identified as one of the most effective candidates for supplementary cementitious material (SCM), because of its large availability. Calcination of clay is achieved via the dehydroxylation reaction, which does not release CO2 (unlike limestone), but has a considerable energy requirement. The required high temperature can be met by electric resistive heating of the working gas in the plant, that can be powered by renewable energy. Therefore, CO2-free calcination of clay can be achieved. Up to 50\% of the limestone-based clinker can be substituted by calcined clay (CC), making the cement more sustainable. We consider a plant that consists of gas-material cyclones that pre-heat the clay, a calciner, and a gas-recirculation system with electric heating of the gas. The model is formulated as a system of differential-algebraic equations (DAE). The model consists of thermophysical properties, reaction kinetics and stoichiometry, transport, mass and energy balances, and algebraic constraints. The model can be used to perform dynamic simulations with changing inputs, process design, and optimization. Moreover, it can be used to develop model-based control, which is relevant for flexible operation of a clay calcination plant for green cement production.

Alice Di Bella, Toni Seibold, Tom Brown et al.

This study analyzes how Europe can decarbonize its industrial sector while remaining competitive. Using the open-source model PyPSA-Eur, it examines key energy- and emission-intensive industries, including steel, cement, methanol, ammonia, and high-value chemicals. Two development paths are explored: a continued decline in industrial activity and a reindustrialization driven by competitiveness policies. The analysis assesses cost gaps between European green products and lower-cost imports, and evaluates strategies such as intra-European relocation, selective imports of green intermediates, and targeted subsidies. Results show that deep industrial decarbonization is technically feasible, led by electrification, but competitiveness depends strongly on policy choices. Imports of green intermediates can lower costs while preserving jobs and production, whereas broad subsidies are economically unsustainable. Effective policy should focus support on sectors like ammonia and steel finishing while maintaining current production levels.

Weiguo Shen, L. Yi, B. Yan et al.

Hannes Kolasch, Franziska Mais

In the decarbonization of the steel, cement, and chemical industries in Germany, green hydrogen is expected to play a crucial role. The utilization of green hydrogen in the production processes of said industries requires organizations to modify their business model, requiring sustainable business model innovation (SBMI). Numerous tools and frameworks that support organizations in the process of SBMI have been proposed in the literature in recent years. However, the applicability of these tools and frameworks for steel, cement, and chemical companies that intend to utilize green hydrogen to produce their goods remains unexplored. This paper aims to assess the suitability of SBMI tools and frameworks for steel, cement, and chemical companies planning to use green hydrogen in their production. It conducts a systematic literature review on SBMI tools and frameworks, reviews current green hydrogen projects in these industries, and evaluates the identified tools and frameworks using an evaluation matrix. Based on the evaluation, the Cambridge Business Model Innovation Process (CBMIP) was identified as the most suitable SBMI framework.

José Luis Velázquez Ortega, Alberto Ignacio Guerrero Vergara

Bingham-type fluids are crucial in many industries and in geology. This study examines their behavior in reinforcing fractured rocks. Rheological properties were derived from experimental data of a water-cement mixture. Computational simulations were conducted using Lattice Boltzmann Method, with a modification to the relaxation parameter. Behavior of these mixtures in narrow ducts that widen and narrow suddenly, common in fractured rocks, was analyzed. Comparing Bingham and Newtonian fluids in various duct shapes provided insight into pressure distribution. Findings demonstrate that both cement-water mixtures, with or without addition of cement, adhere to Forchheimer flow patterns. Furthermore, it is observed that Newtonian fluids generate more intense vortices in expansive and contractive areas, resulting in higher pressure drops compared to Bingham plastics. The ultimate goal is to propose a predictive model based on mortar reinforcement for fractured rocks, taking into account rheological properties and water-cement ratio, thus reducing the need for costly experiments.

Liborija Lugović-Mihić, Eva Filija, Vanja Varga et al.

Acrylates and methacrylates, though common in a wide variety of products, especially in the dental industry, can cause adverse skin reactions. These compounds, including 2-hydroxyethyl methacrylate, triethylene glycol dimethacrylate, and bisphenol A-glycidyl methacrylate, are strong contact irritants or allergens. Found in dental prostheses, composite resins, dentin bonding materials, and glass ionomers, they pose a higher risk of exposure for dental personnel. Clinically, acrylate allergies manifest as facial rashes, eczema with cracked skin on fingers (pulpitis), nail dystrophy, and periungual dermatitis. Recently, however, the highest frequency of allergic reactions to acrylates has been observed in the beauty industry due to increased use in artificial nails, eyelashes, and hair extensions. This has led to greater sensitization. Acrylates are also used in medical applications such as bone cement for orthopedic endoprostheses, soft contact lenses, hearing aids, histological preparations, and wound dressings, which can also cause allergic reactions. For example, acrylates in surgical glue can cause severe dermatitis, and diabetic medical devices are also potential sources of allergic contact dermatitis. Given the extensive use and prolonged skin contact of products containing acrylates and methacrylates, this review aims to present current knowledge from the literature on reactions to these compounds across different industries.

AN Dongqi, CHENG Qianni, SONG Wang et al.

The strict control of nitrogen oxides (NO_x) is an urgent task for improving China′s air quality, and selective catalytic reduction (SCR) with ammonia represents the dominant method for treatment of NO_x exhaust from industries. As the focus of SCR denitrification shifts from thermal power plants to non-electric industries such as steel and cement kilns, the overall working temperature of SCR shows an obvious shift to lower temperatures. Specifically, the flue gas temperature for denitrification is usually below 150 ℃ when a desulfurization treatment is pre-installed. Under these circumstances, achieving long-term and stable operation of denitrification catalysts becomes a pivotal challenge for the application of SCR technology. A decrease in reaction temperature can exacerbate not only water and sulfur poisoning but also induce new deactivation problems due to ammonium nitrate deposition. Therefore, this comprehensive review presents the research progress on the poisoning resistance of SCR catalysts under ultra-low temperatures. The paper starts with introducing the changes in denitrification performance caused by temperature reduction. After briefly describing catalyst deactivation and its characteristics, the main focus is on the developed poisoning resistance strategies against water/sulfur/ammonium nitrate. These strategies are discussed from the perspectives of denitrification catalyst structure modulation, combined purification process selection, and regulation of the reaction atmosphere. Furthermore, we introduce the research progress on anti-poisoning strategies and provide a discussion of anti-poisoning mechanism. Finally, considering the practical application requirements, a prospect for the future development direction of poisoning resistance studies in ultra-low temperature denitrification is presented.

Marta Gandiglio, Paolo Marocco

The global momentum towards hydrogen has led to various initiatives aimed at harnessing hydrogen’s potential. In particular, low-carbon hydrogen is recognized for its crucial role in reducing greenhouse gas emissions across hard-to-abate sectors such as steel, cement and heavy-duty transport. This study focuses on the presentation of all hydrogen-related financing initiatives in Italy, providing a comprehensive overview of the various activities and their geographical locations. The examined funding comes from the National Recovery and Resilience Plan (PNRR), from projects directly funded through the Important Projects of Common European Interest (IPCEI) and from several initiatives supported by private companies or other funding sources (hydrogen valleys). Specific calls for proposals within the PNRR initiative outline the allocation of funds, focusing on hydrogen production in brownfield areas (52 expected hydrogen production plants by 2026), hydrogen use in hard-to-abate sectors and the establishment of hydrogen refuelling stations for both road (48 refuelling stations by 2026) and railway transport (10 hydrogen-based railway lines). A detailed description of the funded initiatives (150 in total) is presented, encompassing their geographical location, typology and size (when available), as well as the funding they have received. This overview sheds light on regions prioritising decarbonisation efforts in heavy-duty transport, especially along cross-border commercial routes, as evident in northern Italy. Conversely, some regions concentrate more on local transport, typically buses, or on the industrial sector, primarily steel and chemical industries. Additionally, the study presents initiatives aimed at strengthening the national manufacturing capacity for hydrogen-related technologies, alongside new regulatory and incentive schemes for hydrogen. The ultimate goal of this analysis is to foster connections among existing and planned projects, stimulate new initiatives along the entire hydrogen value chain, raise an awareness of hydrogen among stakeholders and promote cooperation and international competitiveness.

E. T. Stepkowska, J. M. Blanes, F. Franco et al.

The standard cement paste (C-43-St) was studied previously by static heating, SH, immediately after 1 month hydration at w/c = 0.4 [J. Therm. Anal. Calorim. 69 (2002) 187]. This paste after 5-year ageing (unprotected from contact with air) was subject to thermal analysis in air and in argon (DTA, DTG and TG), to XRD at various temperatures, T, in a high temperature chamber, to mass spectroscopy (MS) and to IR spectroscopy. The aim of this study was to compare the results of SH (fresh paste) and of TG (the aged one), to verify the assumptions made on SH interpretation and to check the change in hydration products with ageing as measured by phase transformation on heating (deltaM versus the final mass).